The present invention generally relates to fuel-fired heating appliances and, in a preferred embodiment thereof, more particularly provides a gas-fired water heater having incorporated therein a specially designed combustion air shutoff system.
Gas-fired residential and commercial water heaters are generally formed to include a vertical cylindrical water storage tank with a gas burner disposed in a combustion chamber below the tank. The burner is supplied with a fuel gas through a gas supply line, and combustion air through one or more air inlet openings providing communication between ambient air and the interior of the combustion chamber.
Water heaters of this general type are extremely safe and quite reliable in operation. However, under certain operational conditions the temperature within the combustion chamber may rise to an undesirable level. Accordingly, it would be desirable, from an improved overall control standpoint, to incorporate in this type of fuel-fired water heater a system for sensing this undesirable combustion chamber temperature rise and responsively terminating the firing of the water heater. It is to this goal that the present invention is directed.